TY  - RPRT
TI  - Stump and tree nesting by mallards and black ducks
AU  - Lewis M. Cowardin
AU  - G.E. Cummings
AU  - P.B. Reed
PY  - 1967
DO  - 10.2307/3798311
UR  - https://pubs.usgs.gov/publication/1001416
ID  - 1001416
ER  -